1. Field of the Invention
Generally, the present invention relates to surgical devices. More specifically, the present invention relates to surgical devices for closing incisions, and fastening tissues and prostheses.
2. Description of Related Art
Minimally invasive surgery has allowed physicians to carry out many surgical procedures with less pain and disability than conventional, open surgery. In performing minimally invasive surgery, the surgeon makes a number of small incisions through the body wall to obtain access to the tissues requiring treatment. Typically, a trocar, which is a pointed, piercing device, is delivered into the body with a cannula. After the trocar pierces the abdominal or thoracic wall, it is removed and the cannula is left with one end in the body cavity, where the operation is to take place, and the other end opening to the outside. A cannula has a small inside diameter, generally 3-10 millimeters. A number of such cannulas are inserted for any given operation.
A viewing instrument, typically including a miniaturized video camera, is inserted through one of these cannulas and a variety of surgical instruments and retractors are inserted through others. The image provided by the viewing device may be displayed on a video screen or television monitor, affording the surgeon enhanced visual control over the instruments. Because a commonly used viewing instrument is called an “endoscope,” this type of surgery is often referred to as “endoscopic surgery.” In the abdomen, endoscopic procedures are commonly referred to as laparoscopic surgery, and in the chest, as thoracoscopic surgery. Abdominal procedures may take place either inside the abdominal cavity (in the intraperitoneal space) or in a space created behind the abdominal cavity (in the retroperitoneal space). The retroperitoneal space is particularly useful for operations on the aorta and spine.
Minimally invasive surgery has virtually replaced open surgical techniques for operations such as cholecystectomy and anti-reflux surgery of the esophagus and stomach. This has not occurred in either peripheral vascular surgery or cardiovascular surgery. An important type of vascular surgery is to replace or bypass a diseased, occluded or injured artery. Arterial replacement or bypass grafting has been performed for many years using open surgical techniques and a variety of prosthetic grafts. These grafts are manufactured as fabrics (often from Dacron or Teflon) or are prepared as autografts (from the patient's own tissues) or heterografts (from the tissues of animals). A graft can be joined to the involved artery in a number of different positions, including end-to-end, end-to-side, and side-to-side. This attachment between artery and graft is known as an anastomosis. Constructing an arterial anastomosis is technically challenging for a surgeon in open surgical procedures, and is almost a technical impossibility using minimally invasive techniques.
Minimally invasive surgery is of interest in cardiovascular surgery because of the nature of the tissue of the heart. Cells known as myocytes beat together in unison in a healthy heart when ion channels open and close in an organized manner. Ions pass in and out of the channels, and the change in concentration of ions from within a cell to outside of a cell results in an electrical potential, causing the cell itself to depolarize and repolarize. The depolarization of one cell triggers the cell next to it to depolarize, and thus a cascade effect of depolarization of all the myocytes is triggered and the heart beats. Making several incisions can interrupt this cascade during surgery and change the beating of the heart. Keeping incisions to a minimum with minimally invasive techniques will allow beating heart surgery to be successful while maintaining the electrical integrity of the heart.
Many factors contribute to the difficulty of performing arterial replacement or bypass grafting. See generally, Wylie, Edwin J. et al., Manual of Vascular Surgery, (Springer-Verlag New York), 1980. One such factor is that the tissues to be joined must be precisely aligned with respect to each other to ensure the integrity and patency of the anastomosis. If one of the tissues is affixed too close to its edge, the suture can rip through the tissue and impair both the tissue and the anastomosis. Another factor is that, even after the tissues are properly aligned, it is difficult and time consuming to pass the needle through the tissues, form the knot in the suture material, and ensure that the suture material does not become tangled. These difficulties are exacerbated by the small size of the artery and graft. The arteries subject to peripheral vascular and cardiovascular surgery typically range in diameter from several millimeters to several centimeters. A graft is typically about the same size as the artery to which it is being attached. Another factor contributing to the difficulty of such procedures is the limited time available to complete the procedure. The time the surgeon has to complete an arterial replacement or bypass graft is limited because there is no blood flowing through the artery while the procedure is being done. If blood flow is not promptly restored, sometimes in as little as thirty minutes, the tissue the artery supplies may experience significant damage, or even death (tissue necrosis). In addition, arterial replacement or bypass grafting is made more difficult by the need to accurately place and space many sutures to achieve a permanent hemostatic seal. Precise placement and spacing of sutures is also required to achieve an anastomosis with long-term patency.
Highly trained and experienced surgeons are able to perform arterial replacement and bypass grafting in open surgery using conventional sutures and suturing techniques. A suture has a suture needle that is attached or “swedged on” to a long, trailing suture material. The needle must be precisely controlled and accurately placed through both graft and artery. The trailing suture material must be held with proper tension to keep the graft and artery together, and must be carefully manipulated to prevent the suture material from tangling. In open surgery, these maneuvers can usually be accomplished within the necessary time frame, thus avoiding the subsequent tissue damage (or tissue death) that can result from prolonged occlusion of arterial blood flow.
The difficulty of suturing a graft to an artery using minimally invasive surgical techniques has effectively prevented the safe use of this technology in both peripheral vascular and cardiovascular surgical procedures. In some minimally invasive procedures, such as those in the abdominal cavity, the retroperitoneal space, or chest, the space in which the operation is performed is more limited. The exposure to the involved organs is also more restricted than with open surgery. Moreover, in a minimally invasive procedure, the instruments used to assist with the operation are passed into the surgical field through cannulas. When manipulating instruments through cannulas, it is extremely difficult to position tissues in their proper alignment with respect to each other, pass a needle through the tissues, form a knot in the suture material once the tissues are aligned, and prevent the suture material from becoming tangled. Therefore, although there have been isolated reports of vascular anastomoses being formed by minimally invasive surgery, no system has been provided for wide-spread surgical use which would allow such procedures to be performed safely within the prescribed time limits.
Recent advances in medical imagining technology coupled with advances in computer-based image processing and modeling capabilities have given physicians an unprecedented ability to visualize anatomical structures in live patients, and to use this information in diagnosis and treatment planning. The precision of image-based pre-surgical planning often greatly exceeds the precision of actual surgical execution. Precise surgical execution has been limited to procedures, such as brain biopsies, in which a suitable sterotactic frame is available. The inconvenience and restricted applicability of such a frame or device has led many researchers to explore the use of robotic devices to augment a surgeon's ability to perform geometrically precise tasks planned from computed tomography (CT) or other image data. The ultimate goal of this research is partnership between a man (the surgeon) and machines (computers and robots), that seeks to exploit the capabilities of both, to do a task better than either can do alone. Machines are very precise and untiring and can be equipped with any number of sensory feedback devices. Numerically controlled robots can move a surgical instrument through an exactly defined trajectory with precisely controlled forces. On the other hand, surgeons are very dexterous. They are also quite strong, fast, and are highly trained to exploit a variety of tactile, visual, and other cues. “Judgmentally” controlled, a surgeon understands what is going on in the surgery and uses dexterity, senses, and experience to execute the procedure. However, the surgeon usually wants to be in control of everything that goes on. If the surgeons desire to increase precision within acceptable limits of time or with sufficient speed, they must be willing to rely on machines to provide the precision.
As explained above, anastomoses are commonly formed in open surgery by suturing together the tissues to be joined. However, one known system for applying a clip around tissues to be joined in an anastomosis is disclosed in a brochure entitled, “VCS Clip Applier System”, published in 1995 by Auto Suture Company, a Division of U.S. Surgical Corporation. A clip is applied by an applying instrument about the tissues in a nonpenetrating manner, i.e., the clip does not penetrate through the tissues, but rather is clamped down around the tissues. As previously explained, it is imperative in forming an anastomosis that tissues to be joined are properly aligned with respect to each other. The disclosed VCS clip applier has no means for positioning tissues. Before the clip can be applied, the tissues must first be grasped and properly positioned with respect to each other, for example by skewering the tissues with a needle as in common suturing techniques and/or with forceps to bring the tissues together. As discussed, it is extremely difficult to perform such positioning techniques in minimally invasive procedures. Coalescent Surgical, Inc. also produces the U-CLIP Anastomotic Device based on self-closing clip technology of nitinol, which eliminates knot tying. The disadvantage of this system is that the surgeon needs to guide the needle from the graft through the native tissue before the U-CLIP can be deployed to suture the tissue. Therefore, there is a need for a system that does not require the surgeon to add an additional step of actively piercing the tissue before applying a suture in anastomosis. There is also a need for a system that has an automatic knot to keep the suture from migrating in the tissue, so that one would not need to be tied by hand by the surgeon. Other sutures have pointed ends that stick out and are not well suited for microsurgery within a tissue or hollow tissue. This can be uncomfortable for the patient, so a suture that has a low profile end sticking out of the tissue is needed. It is also of interest to develop a suture that can be used in beating heart surgery in order to affix a periocardial patch in the heart.
Besides the minimal invasive surgery, a new stage of treatment has been performed with interventional cardiology that is based in the use of balloons, stents, and other devices. The balloons occlude the vessels such that the therapies must be very short. Also, it is not simple to find the exact site of injury. The devices commonly used are occluders systems, coils, or umbrellas. Although these devices are able to fix a defect, the effectiveness of the device depends on the expertise of the surgeon to find the ideal device for the defect. This is important because after the implantation, the defect adapts itself to the device, specifically the umbrellas.
The occluder devices like the umbrellas type have numerous disadvantages, including, but not limited to, a negative effect in the heart compliance and a negative effect in the dynamic heart development. Negative effects in the cardiac conduction system, in conjunction with blockades, can lead a patient to a sudden death. There is a source of thrombotic formation in the left side that can cause serious neurological complications and can also produce perforations of several bordering structures, causing complications, like shunts between the aorta and auricles, and cardiac taponade among others.
Stents have great problems with the re-stenosis, the rupture of their structure, and all the negative effects in hemodynamics, such as losing a vessel's compliance and elasticity. The devices remain in place for extended periods of time in the heart. The devices can cause local inflammation and the long-term results are unknown. The devices can be corroded and/or migrate, producing future complications. An innumerate number of opened questions exist with regard to the effects that these devices produce in other diseases and how much they can affect the future diagnostic and therapeutic methods.
It would be useful to develop a new and improved self-piercing suture and method of using the same, wherein the suture effectively holds tissues together while not migrating in the tissue.